calendar/apps/web/middleware.ts

import { collectEvents } from "next-collect/server";
import { NextMiddleware, NextResponse } from "next/server";

import { extendEventData, nextCollectBasicSettings } from "@calcom/lib/telemetry";

const V2_WHITELIST = ["/settings/admin"];

const middleware: NextMiddleware = async (req) => {
  const url = req.nextUrl;

  /** Display available V2 pages to users who opted-in to early access */
  if (req.cookies.has("calcom-v2-early-access") && V2_WHITELIST.some((p) => url.pathname.startsWith(p))) {
    // rewrite to the current subdomain under the pages/sites folder
    url.pathname = `/v2${url.pathname}`;
  }

  return NextResponse.rewrite(url);
};

export default collectEvents({
  middleware,
  ...nextCollectBasicSettings,
  cookieName: "__clnds",
  extend: extendEventData,
});